1. Field of the Invention
The present invention relates to spectacle frames, and more particularly to articulated nose supports for spectacle frames, where a pair of nose pads is pivotably connect to two stem arms, the constituent parts of each pivot connection being a bracket insert protruding from the nose pad and a stem frame surrounding the bracket insert.
2. DESCRIPTION OF THE PRIOR ART
In conventional articulated nose supports for spectacle frames the bracket insert, protruding from the nose pad, takes the shape of an ear with a transverse pivot bore, while the cooperating stem frame has an aligned throughbore on one side portion and a threaded bore on the opposite side portion. A small screw, which may have an enlarged smooth shaft and a shoulder limiting its penetration into the threaded bore of the stem frame, serves as a pivot pin in cooperation with the pivot bore of the bracket insert.
The manufacturing costs of this type of articulated nose support are comparatively high, because the throughbore and the threaded bore of the stem frame required separate machining operations on the stem frame. Futhermore, particular care is necessary during assembly, because of the minature size of the pivot screw. Lastly, this design has the shortcoming of allowing only for a few threads in the threaded bore of the stem frame, so that assembly and disassembly of the pivot connection entails the risk that the threads are stripped from the stem frame, producing a situation which is difficult to repair.
Another prior art nose support of this type features a modified stem frame in which the pivot screw is replaced with oppositely aligned inwardly facing protrusions on the stem frame which engage the pivot bore of the bracket insert, thereby serving as trunnions. The bracket insert in this case is comparatively massive in thickness, having a thinner base plate embedded in the injection-molded nose pad. This pivot connection, though comparatively simple in terms of manufacturing costs, has the disadvantage that a special tool is required for the assembly of the constituent parts of the pivot connection. Such a structure is proposed in the Japanese Utility Model Publication No. 31 356/1974, FIGS. 1 and 2. In FIG. 3 of this publication is shown the first-mentioned prior art pivot connection using a pivot screw.